1. Field of the Invention
The present invention relates generally to a speaker applicable to various electronic devices, and in particular, to a speaker with an auxiliary air hole, which is configured to ensure sufficient sound volume and quality by allowing smooth discharge of air generated in the speaker as a result of vibration of a diaphragm.
2. Description of the Related Art
In general, a speaker is operated by interaction between a magnet on a body having a circular receiving part, and a diaphragm provided with a voice coil installed at a predetermined distance from the magnet. When a drive signal is applied to the voice coil, the coil moves up or down according to a direction of a magnetic force line of the magnet, and the intensity and direction of an electromagnetic force line of the voice coil. At this time, the diaphragm vibrates together with the coil. The operation of the diaphragm is repetitively made and thus sound pressure is generated, so that the speaker outputs a sound within an audible frequency range.
In response to users' demands, small-sized electronic devices using the aforementioned speakers, such as a mobile terminal, an MP3 player, and the like, are becoming lower in volume and increasing their functionality. As for mobile terminals, a so-called ‘slim phone’ that has a slim profile resulting from minimizing the entire thickness of a device is being released, requiring the miniaturization of various components mounted in such a device.
When the aforementioned speaker is applied to such a device, a rear surface of the speaker, where no sound is output, is substantially attached to a case frame of the device.
However, the attachment between the rear surface of the speaker and the case frame of the device causes an inner surface of the case frame to block an air hole that is formed at the rear surface of the speaker and serves to discharge air generated by the vibration of the diaphragm. As a result, the air discharge is hindered, which results in a relative small sound volume and degradation in sound quality.